1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2017 Red Hat, Inc.
9 #include <linux/compat.h>
10 #include <linux/fileattr.h>
11 #include <linux/fsverity.h>
13 static ssize_t fuse_send_ioctl(struct fuse_mount *fm, struct fuse_args *args,
14 struct fuse_ioctl_out *outarg)
18 args->out_args[0].size = sizeof(*outarg);
19 args->out_args[0].value = outarg;
21 ret = fuse_simple_request(fm, args);
23 /* Translate ENOSYS, which shouldn't be returned from fs */
27 if (ret >= 0 && outarg->result == -ENOSYS)
28 outarg->result = -ENOTTY;
34 * CUSE servers compiled on 32bit broke on 64bit kernels because the
35 * ABI was defined to be 'struct iovec' which is different on 32bit
36 * and 64bit. Fortunately we can determine which structure the server
37 * used from the size of the reply.
39 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
40 size_t transferred, unsigned count,
44 if (count * sizeof(struct compat_iovec) == transferred) {
45 struct compat_iovec *ciov = src;
49 * With this interface a 32bit server cannot support
50 * non-compat (i.e. ones coming from 64bit apps) ioctl
56 for (i = 0; i < count; i++) {
57 dst[i].iov_base = compat_ptr(ciov[i].iov_base);
58 dst[i].iov_len = ciov[i].iov_len;
64 if (count * sizeof(struct iovec) != transferred)
67 memcpy(dst, src, transferred);
71 /* Make sure iov_length() won't overflow */
72 static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov,
76 u32 max = fc->max_pages << PAGE_SHIFT;
78 for (n = 0; n < count; n++, iov++) {
79 if (iov->iov_len > (size_t) max)
86 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
87 void *src, size_t transferred, unsigned count,
91 struct fuse_ioctl_iovec *fiov = src;
94 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
98 if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
101 for (i = 0; i < count; i++) {
102 /* Did the server supply an inappropriate value? */
103 if (fiov[i].base != (unsigned long) fiov[i].base ||
104 fiov[i].len != (unsigned long) fiov[i].len)
107 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
108 dst[i].iov_len = (size_t) fiov[i].len;
112 (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
113 (compat_size_t) dst[i].iov_len != fiov[i].len))
121 /* For fs-verity, determine iov lengths from input */
122 static int fuse_setup_measure_verity(unsigned long arg, struct iovec *iov)
125 struct fsverity_digest __user *uarg = (void __user *)arg;
127 if (copy_from_user(&digest_size, &uarg->digest_size, sizeof(digest_size)))
130 if (digest_size > SIZE_MAX - sizeof(struct fsverity_digest))
133 iov->iov_len = sizeof(struct fsverity_digest) + digest_size;
138 static int fuse_setup_enable_verity(unsigned long arg, struct iovec *iov,
139 unsigned int *in_iovs)
141 struct fsverity_enable_arg enable;
142 struct fsverity_enable_arg __user *uarg = (void __user *)arg;
143 const __u32 max_buffer_len = FUSE_MAX_MAX_PAGES * PAGE_SIZE;
145 if (copy_from_user(&enable, uarg, sizeof(enable)))
148 if (enable.salt_size > max_buffer_len || enable.sig_size > max_buffer_len)
151 if (enable.salt_size > 0) {
155 iov->iov_base = u64_to_user_ptr(enable.salt_ptr);
156 iov->iov_len = enable.salt_size;
159 if (enable.sig_size > 0) {
163 iov->iov_base = u64_to_user_ptr(enable.sig_ptr);
164 iov->iov_len = enable.sig_size;
170 * For ioctls, there is no generic way to determine how much memory
171 * needs to be read and/or written. Furthermore, ioctls are allowed
172 * to dereference the passed pointer, so the parameter requires deep
173 * copying but FUSE has no idea whatsoever about what to copy in or
176 * This is solved by allowing FUSE server to retry ioctl with
177 * necessary in/out iovecs. Let's assume the ioctl implementation
178 * needs to read in the following structure.
185 * On the first callout to FUSE server, inarg->in_size and
186 * inarg->out_size will be NULL; then, the server completes the ioctl
187 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
188 * the actual iov array to
190 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
192 * which tells FUSE to copy in the requested area and retry the ioctl.
193 * On the second round, the server has access to the structure and
194 * from that it can tell what to look for next, so on the invocation,
195 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
197 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
198 * { .iov_base = a.buf, .iov_len = a.buflen } }
200 * FUSE will copy both struct a and the pointed buffer from the
201 * process doing the ioctl and retry ioctl with both struct a and the
204 * This time, FUSE server has everything it needs and completes ioctl
205 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
207 * Copying data out works the same way.
209 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
210 * automatically initializes in and out iovs by decoding @cmd with
211 * _IOC_* macros and the server is not allowed to request RETRY. This
212 * limits ioctl data transfers to well-formed ioctls and is the forced
213 * behavior for all FUSE servers.
215 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
218 struct fuse_file *ff = file->private_data;
219 struct fuse_mount *fm = ff->fm;
220 struct fuse_ioctl_in inarg = {
226 struct fuse_ioctl_out outarg;
227 struct iovec *iov_page = NULL;
228 struct iovec *in_iov = NULL, *out_iov = NULL;
229 unsigned int in_iovs = 0, out_iovs = 0, max_pages;
230 size_t in_size, out_size, c;
234 struct fuse_args_pages ap = {};
236 #if BITS_PER_LONG == 32
237 inarg.flags |= FUSE_IOCTL_32BIT;
239 if (flags & FUSE_IOCTL_COMPAT) {
240 inarg.flags |= FUSE_IOCTL_32BIT;
241 #ifdef CONFIG_X86_X32_ABI
242 if (in_x32_syscall())
243 inarg.flags |= FUSE_IOCTL_COMPAT_X32;
248 /* assume all the iovs returned by client always fits in a page */
249 BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
252 ap.pages = fuse_pages_alloc(fm->fc->max_pages, GFP_KERNEL, &ap.descs);
253 iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
254 if (!ap.pages || !iov_page)
257 fuse_page_descs_length_init(ap.descs, 0, fm->fc->max_pages);
260 * If restricted, initialize IO parameters as encoded in @cmd.
261 * RETRY from server is not allowed.
263 if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
264 struct iovec *iov = iov_page;
266 iov->iov_base = (void __user *)arg;
267 iov->iov_len = _IOC_SIZE(cmd);
269 if (_IOC_DIR(cmd) & _IOC_WRITE) {
274 if (_IOC_DIR(cmd) & _IOC_READ) {
281 case FS_IOC_MEASURE_VERITY:
282 err = fuse_setup_measure_verity(arg, iov);
284 case FS_IOC_ENABLE_VERITY:
285 err = fuse_setup_enable_verity(arg, iov, &in_iovs);
293 inarg.in_size = in_size = iov_length(in_iov, in_iovs);
294 inarg.out_size = out_size = iov_length(out_iov, out_iovs);
297 * Out data can be used either for actual out data or iovs,
298 * make sure there always is at least one page.
300 out_size = max_t(size_t, out_size, PAGE_SIZE);
301 max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
303 /* make sure there are enough buffer pages and init request with them */
305 if (max_pages > fm->fc->max_pages)
307 while (ap.num_pages < max_pages) {
308 ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
309 if (!ap.pages[ap.num_pages])
315 /* okay, let's send it to the client */
316 ap.args.opcode = FUSE_IOCTL;
317 ap.args.nodeid = ff->nodeid;
318 ap.args.in_numargs = 1;
319 ap.args.in_args[0].size = sizeof(inarg);
320 ap.args.in_args[0].value = &inarg;
322 ap.args.in_numargs++;
323 ap.args.in_args[1].size = in_size;
324 ap.args.in_pages = true;
327 iov_iter_init(&ii, ITER_SOURCE, in_iov, in_iovs, in_size);
328 for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
329 c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
330 if (c != PAGE_SIZE && iov_iter_count(&ii))
335 ap.args.out_numargs = 2;
336 ap.args.out_args[1].size = out_size;
337 ap.args.out_pages = true;
338 ap.args.out_argvar = true;
340 transferred = fuse_send_ioctl(fm, &ap.args, &outarg);
345 /* did it ask for retry? */
346 if (outarg.flags & FUSE_IOCTL_RETRY) {
349 /* no retry if in restricted mode */
351 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
354 in_iovs = outarg.in_iovs;
355 out_iovs = outarg.out_iovs;
358 * Make sure things are in boundary, separate checks
359 * are to protect against overflow.
362 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
363 out_iovs > FUSE_IOCTL_MAX_IOV ||
364 in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
367 vaddr = kmap_local_page(ap.pages[0]);
368 err = fuse_copy_ioctl_iovec(fm->fc, iov_page, vaddr,
369 transferred, in_iovs + out_iovs,
370 (flags & FUSE_IOCTL_COMPAT) != 0);
376 out_iov = in_iov + in_iovs;
378 err = fuse_verify_ioctl_iov(fm->fc, in_iov, in_iovs);
382 err = fuse_verify_ioctl_iov(fm->fc, out_iov, out_iovs);
390 if (transferred > inarg.out_size)
394 iov_iter_init(&ii, ITER_DEST, out_iov, out_iovs, transferred);
395 for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
396 c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
397 if (c != PAGE_SIZE && iov_iter_count(&ii))
402 free_page((unsigned long) iov_page);
404 __free_page(ap.pages[--ap.num_pages]);
407 return err ? err : outarg.result;
409 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
411 long fuse_ioctl_common(struct file *file, unsigned int cmd,
412 unsigned long arg, unsigned int flags)
414 struct inode *inode = file_inode(file);
415 struct fuse_conn *fc = get_fuse_conn(inode);
417 if (!fuse_allow_current_process(fc))
420 if (fuse_is_bad(inode))
423 return fuse_do_ioctl(file, cmd, arg, flags);
426 long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
428 return fuse_ioctl_common(file, cmd, arg, 0);
431 long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
434 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
437 static int fuse_priv_ioctl(struct inode *inode, struct fuse_file *ff,
438 unsigned int cmd, void *ptr, size_t size)
440 struct fuse_mount *fm = ff->fm;
441 struct fuse_ioctl_in inarg;
442 struct fuse_ioctl_out outarg;
446 memset(&inarg, 0, sizeof(inarg));
450 #if BITS_PER_LONG == 32
451 inarg.flags |= FUSE_IOCTL_32BIT;
453 if (S_ISDIR(inode->i_mode))
454 inarg.flags |= FUSE_IOCTL_DIR;
456 if (_IOC_DIR(cmd) & _IOC_READ)
457 inarg.out_size = size;
458 if (_IOC_DIR(cmd) & _IOC_WRITE)
459 inarg.in_size = size;
461 args.opcode = FUSE_IOCTL;
462 args.nodeid = ff->nodeid;
464 args.in_args[0].size = sizeof(inarg);
465 args.in_args[0].value = &inarg;
466 args.in_args[1].size = inarg.in_size;
467 args.in_args[1].value = ptr;
468 args.out_numargs = 2;
469 args.out_args[1].size = inarg.out_size;
470 args.out_args[1].value = ptr;
472 err = fuse_send_ioctl(fm, &args, &outarg);
474 if (outarg.result < 0)
476 else if (outarg.flags & FUSE_IOCTL_RETRY)
482 static struct fuse_file *fuse_priv_ioctl_prepare(struct inode *inode)
484 struct fuse_mount *fm = get_fuse_mount(inode);
485 bool isdir = S_ISDIR(inode->i_mode);
487 if (!fuse_allow_current_process(fm->fc))
488 return ERR_PTR(-EACCES);
490 if (fuse_is_bad(inode))
491 return ERR_PTR(-EIO);
493 if (!S_ISREG(inode->i_mode) && !isdir)
494 return ERR_PTR(-ENOTTY);
496 return fuse_file_open(fm, get_node_id(inode), O_RDONLY, isdir);
499 static void fuse_priv_ioctl_cleanup(struct inode *inode, struct fuse_file *ff)
501 fuse_file_release(inode, ff, O_RDONLY, NULL, S_ISDIR(inode->i_mode));
504 int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa)
506 struct inode *inode = d_inode(dentry);
507 struct fuse_file *ff;
512 ff = fuse_priv_ioctl_prepare(inode);
516 if (fa->flags_valid) {
517 err = fuse_priv_ioctl(inode, ff, FS_IOC_GETFLAGS,
518 &flags, sizeof(flags));
522 fileattr_fill_flags(fa, flags);
524 err = fuse_priv_ioctl(inode, ff, FS_IOC_FSGETXATTR,
529 fileattr_fill_xflags(fa, xfa.fsx_xflags);
530 fa->fsx_extsize = xfa.fsx_extsize;
531 fa->fsx_nextents = xfa.fsx_nextents;
532 fa->fsx_projid = xfa.fsx_projid;
533 fa->fsx_cowextsize = xfa.fsx_cowextsize;
536 fuse_priv_ioctl_cleanup(inode, ff);
541 int fuse_fileattr_set(struct mnt_idmap *idmap,
542 struct dentry *dentry, struct fileattr *fa)
544 struct inode *inode = d_inode(dentry);
545 struct fuse_file *ff;
546 unsigned int flags = fa->flags;
550 ff = fuse_priv_ioctl_prepare(inode);
554 if (fa->flags_valid) {
555 err = fuse_priv_ioctl(inode, ff, FS_IOC_SETFLAGS,
556 &flags, sizeof(flags));
560 memset(&xfa, 0, sizeof(xfa));
561 xfa.fsx_xflags = fa->fsx_xflags;
562 xfa.fsx_extsize = fa->fsx_extsize;
563 xfa.fsx_nextents = fa->fsx_nextents;
564 xfa.fsx_projid = fa->fsx_projid;
565 xfa.fsx_cowextsize = fa->fsx_cowextsize;
567 err = fuse_priv_ioctl(inode, ff, FS_IOC_FSSETXATTR,
572 fuse_priv_ioctl_cleanup(inode, ff);